Folding extension leveling rod



March 27, 1962 P. w. GRAFF 3,026,619

FOLDING EXTENSION LEVELING ROD Filed Nov. 29, 1960 2 Sheets-Sheet 2 lppp'l lpllprl 3,2b,619 Patented Mar. 27, 1962 3,026,619 FGLDING EXTENSION LEVELING ROD Paul W. Graif, Biairsville, Pa., assignor to North American Gear-Company, a corporation of Pennsylvania Filed Nov. 29, 1960, Ser. No. 72,334 Claims. (Cl. 33-44) This invention relates to extension leveling rods, such as used by surveyors and the like.

The ordinary extension leveling rod is formed from front and back bars that are slidable lengthwise relative to each other to extend the rod to the desired height. A slide and clamp hold the bars together and in their adjusted positions. Even when such a rod is not extended, it is quite long and awkward to carry in an automobile. It either has to be laid across the front and back seats or fastened to the outside of the car.

It is among the objects of this invention to provide an extension leveling rod which can be folded to half its ordinary length, which can be locked securely in unfolded position, and in which the hinging and locking means will not interfere with extending the rod or moving a target up and down the rod.

In accordance with this invention, the leveling rod has a vertical back bar engaging a front bar on which it is slidable upwardly. A slide is secured to the lower part of the back bar and extends around the front bar in sliding engagement with its sides and front. Secured to the upper part of thefront bar is a clamp that extends around the back bar in'sliding' engagement with its sides and back. The two bars are divided centrally in'the same transverse plane into upper and lower sections. On one side of. the

bars there are hinges that hinge the upper and lower sections together to permit the rod to be folded. Removable internal locking devices normally hold the sections in end to end alignment. The slide and clamp are provided at the hinged side of the bars with inwardly opening vertical channels therethrough, so that when the back bar is slid up the front bar thesilde can pass over the hinge on the front bar, and the back hinge can pass up through the clamp.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a front view, with parts broken away, of my extension leveling rod;

FIG. 2 is a rear view of the rod;

FIG. 3 is a view of the hinged side of the rod;

FIG. 4 is a fragmentary side view of the other side of the rod, taken along the line IVIV of FIG. 1 but showing the rear bar raised;

FIGS. 5 and 6 are enlarged cross sections taken on the lines VV and VIVI, respectively, of FIG. 1; and

FIG. 7 is an enlarged cross section taken on the line VIIVII of FIG. 1, but with the rear bar partly raised.

Referring to the drawings, the main part of the exten sion leveling rod is formed from a front bar 1 and a rear bar 2 disposed face to face. The bottom of the rear bar is supported by a short foot 3 rigidly connected to the front bar by a shoe 4. The foot may be the same shape as the back bar, which rests on it. The back bar extends a few inches above the front bar and has a head 6 rigidly connected to it by a cap 7. The head may be the same shape as the front bar, on which it rests normally. The lower portions of the two bars are held together by a U-shape slide 8 that has its opposite ends secured to the back bar by bolts 9. The slide engages the opposite sides of the front bar and also the front of that bar. The two bars are therefore held together, but the back one can be slid up and down the front one. To further hold the two bars together and also to retain the back bar in any position to which it may be adjusted on the front bar, a clamp 11 is provided. This clamp likewise is U-shape and has its opposite ends secured to the opposite sides of the upper portion of the front bar by means of bolts 12. The clamp extends back around the back bar in engagement with its sides and rear surface. Inside the clamp, in an inwardly opening vertical channel 13 at one side of the back bar, there is a pressure plate 14 (FIG. 6). To hold the plate in the clamp, the latter is provided with vertically spaced holes, in which are slidably mounted pins 15 that are secured to the back of the plate. The pressure plate normally is pressed against the front bar by a hand screw 16 threaded in the same side of the clamp. This will hold the back bar in any desired vertical position on the front bar.

It is a feature of this invention that in spite of the leveling rod being extendable, it can be folded to half its unextended length. Accordingly, about half way between the ends of the rod it is divided ina transverse plane 17 into upper and lower sections. These sections are hinged together, but normally are locked in end to end alignment. Two hinges 18 are used, one for each bar. They are secured to the upper and lower sections of the bars at side of the rod opposite pressure plate 14 and preferably are countersunk so that onlytheir pivoted knuckles project from the bars.

Various internal locking devices can be used to hold the two sections in alignment. Preferably, however, the locking devices include two horizontal pins 20, one of which is disposed in each bar close to the division plane 17. The bar sections that contain the pins, such as the upper sections, are each provided with a central vertical. 7 socket 21 that receives a tongue-22extending up into it.

from the adjoininglower section of the bar. To permit the tongue to be swung out of the socket when the bar is folded, and to wedge the tongue and socket. together when the bar is straight, the tongue and socket are tapered upwardly in the plane of the adjoining hinge; that is, in a plane parallel to the other bar. Each tongue is provided with a transverse passage 23, preferably in a plane parallel to the other bar. The adjoining socketed section has a passage 24 through it that connects with the tongue passage. One end of passage 24, most suitably the end opposite the hinges, is threaded for receiving the threaded head of pin 20. The pin and passage are tapered toward their opposite end. If the axis of the tongue passage is it is screwed into place, and the rod will be held straightr When the pin is in place, its threaded head is substantially flush with the side of the bar. The outer end of the pin is provided with a socket for a wrench.

Another feature of this invention is that the slide and clamp are formed in such a manner that they and the hinges can pass as the rod is extended to increase its height. This is accomplished, as shown in FIG. 7, by thickening one side of slide 8 and providing it with an inwardly opening vertical channel 26 that is just large enough to slide up past the front hinge when the back bar is raised. The side of clamp 11 opposite to the adjusting screw is provide-d with an inwardly opening vertical channel 27 (FIG. 6) to allow the back hinge to pass up through the clamp when the back bar is raised.

A target 30 is disposed in front of the bars and usually is located at their upper ends. As shown in FIG. 5, it is supported by parallel ribs 31 that extend back across the opposite sides of'the' rod a very short distance and then inwardly into vertical grooves 32, with which the sides of the front bar and the head 6 of the back bar are provided. These grooves are located in front of the clamp and the hinges so that the target can be moved nearly the full length of the rod when it is not extended. The target is held in any desired position by a set screw 33 extending through it and engaging the bar behind it.

The bars of this leveling rod can be formed from wood or metal and have any desired shape in cross section. Preferably, however, they are made from extruded aluminum, and the front of the front bar and both front and back of the back bar are formed for receiving removable scale tapes (not shown) in a well-known manner. The rear scale can be seen through a window 35 (FIG. 2) in the back of clamp 11. The clamp carries the usual vertical vernier scale on a thin strip 36. It also is a feature of this invention that the major portion of each bar section is tubular, but its hinged end portion is solid metal. Thus, each lower section of the bars has a solid member 37 at its upper end seated on the tubular portion and provided with a plug 38 fitting tightly therein, where it is secured in any suitable manner. The exposed part of the solid member has the same exterior contour as the rest of the bar. A similar solid member as, containing socket 21 is plugged into the lower end of the tubular portion of each upper bar section. The

i hinges are fastened to the solid members, and pins 20 l are mounted in the upper ones. The solid pieces form firm connections at the center of the rods when they are i looked in straight position. I

It will be seen that the leveling rod described herein is fully extendable, but that it also can be folded to half the length it otherwise would have when not extended. The folding does not interfere in any way with extending the rod, and when not folded the upper and lower sections of the rod are rigidly connected together to hold them in perfect alignment.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scopeof the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim: 1 A folding extension leveling rod comprising a vertical front bar, a vertical back bar engaging the front bar and slidable upwardly thereon, a slide secured to the lower part of the back bar and extending around the front bar in sliding engagement with its sides and front, a clamp secured to the upper part of the front bar and extending around the back bar in sliding engagement with its sides and back, the two bars being divided centrally in the same transverse plane when the bars are not extended into upper and lower sections, hinges at one side of the bars hinging said upper and lower sections together to permit the rod to be folded, and removable internal locking devices normally holding said sections in end to end alignment, the said slide and clamp aeing provided at the hinged side of the bars with in- ,ardly opening vertical channels therethrough to allow the slide, when the back bar is slid up'the front bar, to piass over the hinge on the front bar and to allow the hinge on the back bar to pass through the clamp.

2. A folding extension leveling rod comprising a vertical front bar, a vertical back bar engaging the front bar and slidable upwardly thereon, a slide secured to the lower part of the back bar and extending around the front bar in sliding engagement with its sides and front, a clamp secured to the upper part of the front bar and extending around the back bar in sliding engagement with its sides and back, the two bars being divided centrally in the same transverse plane when the bars are not extended into upper and lower sections, hinges at one side of the bars hinging said upper and lower sections together to permit the rod to be folded, the upper and lower sections of each bar being provided with an interengaging vertical tongue and socket, each tongue having a transverse passage therethrough, and a removable pin screwed into each socketed bar section and extending into the tongue passage therein to normally hold the adjoining bar sections in end to end alignment, said slide and clamp being provided at the hinged side of the bars with inwardly opening vertical channels therethrough to allow the slide, when the back bar is slid up the front bar, to pass over the hinge on the front bar and to allow the hinge on the back bar to pass through the clamp.

3. A folding extension leveling rod according to claim 2, in which the major portion of each bar section is a tubular member and the hinged end portion is a solid member provided with a plug secured tightly in the adjoining end of said tubular member, said tongues projecting from two of the solid members, and the other two solid members being provided with said sockets.

4. A folding extension leveling rod comprising a vertical front bar, a vertical back bar engaging the front bar and slidable upwardly thereon, a slide secured to the lower part of the back bar and extending around the front bar in sliding engagement with its sides and front, a clamp secured to the upper part of the front bar and extending around the back bar in sliding engagement with its sides and back, the two bars being divided centrally in the same transverseplane when the bars are not extended into upper and lower sections, hinges at one side of the bars hinging said upper and lower sections together to permit the rod to be folded, the hinged end of one section of each bar having a vertical tongue and the adjoining section having a socket snugly receiving the tongue, the tongue and socket being tapered in the plane of the adjoining hinge, the tongue having a transverse passage therethrough in said plane, and a removable pin screwed into the socketed bar section and extending into said tongue passage and normally wedging the tongue in the socket to hold the adjoining bar sections in end to end alignment, said slide and clamp being provided at the hinged side of the bars with inwardly opening vertical channels therethrough to allow the slide, when the back baris slid up the front hinge on the back bar to pass through the clamp.

5. A folding extension leveling rod comprising a vertical front bar, a vertical back bar engaging the front bar and slidable upwardly thereon, a slide secured to the lower part of the back bar and extending around the front bar in sliding engagement with its sides and front, the opposite sides of the rod at its front being provided with vertical grooves, a target in front of the bars, means supporting the target and slidable vertically in said grooves, a U-shape clamp secured to the upper part of the front bar behind said grooves and extending around the back bar in sliding engagement with its sides and back, the two bars being divided centrally in the same transverse plane when the bars are not extended into upper and lower sections, hinges at one side of the bars hinging said upper and lower sections together to permit the rod to be folded, and removable internal locking devices normally holding said sections in end to end alignment, said slide and clamp being provided at the hinged side of the bars with inwardly opening vertical channels therethrough to allow the slide, when the back bar is slid up the front bar, to pass over the hinge on the front bar and to allow the hinge on the back bar to pass through the clamp.

No references cited. 

